Nuclear accident follows Japanese earthqauke

Post by **adam2** » 16 Mar 2011, 04:34

Update here
http://www.bbc.co.uk/news/world-asia-pacific-12755739
Presuming that the report is accurate WRT radiation levels, then these are very high indeed.
Exposure for an hour or two could cause illness, and a working day could cause death.
It sounds as though spent fuel in the cooling ponds may be burning.

Aurora · Post by **Aurora** » 16 Mar 2011, 05:35

BBC News - 04.54am - 16/03/11

Fukushima workers withdraw after radiation spikes

A rise in radiation levels at Japan's stricken Fukushima nuclear plant has forced workers to suspend operations, a government spokesman says.

He was speaking after smoke was seen rising from reactor three. Earlier, a blaze struck reactor four for the second time in two days.

Article continues ...

2 As and a B · Post by **2 As and a B** » 16 Mar 2011, 07:42

Clarifications please, the first two based on what has been written in this forum...

When the casing building of reactor #3 exploded, what were those lumps of stuff that were thrown into the air and fell to ground? Were they spent fuel rods? What were they doing there?

If there are a further 2 reactors (#5 and #6) at Fukushima Daiichi, what and where are they?

Japan is spreading the available electricity around, with planned power cuts. There is clearly no great problem with transmission. Is there a problem with electricity generation? Why, if this nuclear power plant is the only one affected? Are any others out of action?

Aurora · Post by **Aurora** » 16 Mar 2011, 08:06

Economy Watch - 16/03/11

Fukushima GE-Made Reactor's Safety Doubted Since 70's

The warnings were stark and issued repeatedly as far back as 1972:

If the cooling systems ever failed at a Mark 1 nuclear reactor developed in the 1960s by General Electric, the primary containment vessel surrounding the reactor would probably burst as the fuel rods inside overheated.

Dangerous radiation would spew into the environment.

Article continues ...

biffvernon · Post by **biffvernon** » 16 Mar 2011, 08:17

The lumps flying about at #3 were probably bits of roof - slabs of concrete. Fuel rods are much smaller and if there were any they would be lost in the smoke and dust. Spent fuel rods are stored for a while in a 'pond' (not the sort with frogs and ducks) within the big square box building that was blown apart.

#5 and #6 are reactors which, along with #4 were not actually operational at the time but do contain spent fuel and there have been reports that their temperatures are rising.

At least one other nuke is seriously damaged and other that automatically shut down in the quaske have probably not been restarted.

At least we are getting tv pictures from Fukushima now from NHK. The #3 building is a real wreck - roof and at least one wall missing and a lot of mangled plumbing. Smoke and/or steam is rising from #4. Just seen a shot of big helicoptors icking up big buckets of water from the sea, presumably to dump onto the site.

BBC are reporting that the helicopters have to fly over and dump their water quickly to avoid too much radiation to crew.

Tweet:

Japanese government now telling people living within 10-kilometer radius of Daini plant to evac

marknorthfield · Post by **marknorthfield** » 16 Mar 2011, 09:01

So the military are trying the helicopter method after all. The NHK footage of it illustrates the scale and difficulty of the challenge.

The Guardian live feed has quotes from David Hinde, head of the department of nuclear physics at the Australian National University, about this.

8.40am (5.40pm JST): Tania Branigan has been speaking again to Professor David Hinde, head of the department of nuclear physics at the Australian National University. He says that the status of the spent fuel pools at the Fukushima plant is very concerning. Water levels are reportedly dropping in unit 4, and the temperature of the pools in 5 and 6 are now rising.

It is clearly a serious situation now because there is no containment for those spent fuel pools… My feeling is that they are probably a more serious issue now than the reactors, [where] there's at least a degree of containment remaining.

Spent fuel rods are strongly radioactive and the water above them shields against that radiation so as long as the water level is sufficiently high – you can walk up to the edge of the pool and pour a bucket of water in. Once it is even close to the top of the rods the levels are too high to approach the pool, which is clearly what has happened in unit 4.

It's been suggested that the Japanese Self Defence Force could use helicopters to drop water onto the plant (see 8.06am). But even if the military is willing to risk exposing pilots to radiation, Hinde says this is far easier said than done:

My estimates suggest they might need 50 tonnes an hour of water. You could do that easily with a large bore hosepipe but if you are doing it with helicopters it is a lot more difficult – and harder to get the water into the pool. I very much hope they rig up a temporary pipe works in 5 and 6 to pump water in remotely to avoid reaching this situation.

He said the ideal situation would be to re-establish the cooling system, which seems to have been knocked out by the tsunami.

2 As and a B · Post by **2 As and a B** » 16 Mar 2011, 09:01

Thanks for the clarifications Biff. I take it that #1 reactor either didn't have a concrete roof and cooling pond, or it collapsed down after the explosion.

Here is a photo from the Bbc site of what I take to be the remains of #3 and #4, with massive foreshortening of the photo past the mound of earth. I don't think it can be #1 and #2 unless the middle pylon has gone and #3 and #4 have been reduced to near ground level.

PS_RalphW · Post by **PS_RalphW** » 16 Mar 2011, 09:35

Guardian is reporting that the entire site has been evacuated and the helicopters stopped flying due to the radiation levels. Smoke/steam from reactor 3 and fire in reactor 4.

When they wheel out the Emporer to give a moralle boosting speech you know they are in trouble...

The real lesson from this, is don't leave spent fuel rods in uncontained pools near tsunami -prone shores directly on top of old, poorly designed nuclear reactors.

Nuclear reactors can be designed, built and operated in safe ways. In the real world they never are.

2 As and a B · Post by **2 As and a B** » 16 Mar 2011, 09:47

It's all mighty confusing. Here is a recent summary of recent events, however incomplete, from Kyodo News.

Fukushima No. 3 reactor's container feared damaged: Edano

TOKYO, March 16, Kyodo

The containment vessel of the quake-hit No. 3 reactor of the Fukushima No. 1 nuclear power plant may have been damaged, Japan's top government spokesman said Wednesday, indicating that radioactive steam may be spreading outside.

The government's nuclear safety agency said the radiation level briefly reached 10 millisievert per hour at the plant's entrance at 10:40 a.m., but added that it was possibly due to radioactive substances emitted from the No. 2 reactor, as the government and Tokyo Electric Power Co. continued to scramble to address the ongoing nuclear crisis in the wake of Friday's devastating earthquake that hit Japan centering on its northeastern region.

The utility firm is also considering spraying boric acid by helicopter to prevent spent nuclear fuel rods at another troubled reactor, No. 4, from reaching criticality again, restarting a chain reaction.

Earlier Wednesday, a fire broke out again at the No. 4 reactor, which was already posing the risk of leaks of high-level radioactive materials, but flames were no longer visible about 30 minutes later, according to TEPCO.

The No. 3 reactor started to draw more attention after live TV footage of the plant showed white smoke coming out around 10 a.m.

Chief Cabinet Secretary Yukio Edano told a press conference that the smoke has been recognized from around 8:30 a.m. and said, ''There is a possibility that the No. 3 reactor's containment vessel is damaged.''

Edano, however, said that the government has no plans to expand the evacuation area of within 20 kilometers from the plant for now.

As for the No. 4 reactor, the utility said Tuesday that water in a pool storing the spent fuel rods may be boiling and that its level may have dropped, exposing the rods. The government ordered the firm to inject water into the pool ''as soon as possible to avert a major nuclear disaster.''

Due to high radiation levels at the reactor, workers have been unable to pour water into the troubled pool. Difficult conditions have led the utility to evacuate around 730 of the 800 workers from the site, according to TEPCO.

''The possibility of re-criticality is not zero,'' TEPCO said Wednesday as it announced the envisaged step to put the No. 4 reactor under control.

Unless the spent fuel rods are cooled down, they could suffer damage and emit radioactive substances.

An estimated 70 percent of the nuclear fuel rods have been damaged at the plant's No. 1 reactor and 33 percent at the No. 2 reactor, the firm also said. The cores of both reactors are believed to have partially melted with their cooling functions lost in the wake of Friday's magnitude 9.0 earthquake and tsunami.

At the No. 2 reactor, the pressure-suppression chamber connected to its containment vessel was damaged following an apparent hydrogen explosion early Tuesday.

An apparent hydrogen blast also occurred Tuesday morning at the No. 4 reactor, before a worker at the plant saw flames around 5:45 a.m. Wednesday on the fourth floor of the building housing the reactor, believed to be the same spot with the blast that caused a fire the day before. The reactor had been halted for regular checks from before the quake.

biffvernon · Post by **biffvernon** » 16 Mar 2011, 09:47

I guess it behoves all those who, over the last half century, have supported nuclear powwr, to explain why storing spent fuel in ponds that need active cooling systems within the same building as a reactor where hydrogen can accululate to explosive levels was an acceptable situation.

Building in earthquake and tsunami prone areas added to, and has now highlighted, the problem but the design is fundementally flawed irrespective of the location.

2 As and a B · Post by **2 As and a B** » 16 Mar 2011, 10:08

All Fukushima Daini units in cold shutdown

15 March 2011

All four units at the Fukushima Daini nuclear power plant have now achieved cold shutdown - where coolant water is at less than 100ºC - with full operation of cooling systems, Tepco reported. All the reactors shut down automatically during last week's earthquake and have remained safe. While unit 3's shutdown went as expected, damage to the emergency core cooling systems of units 1, 2 and 4 led to the announcement of emergency status. These three reactors were prepared for potential pressure release, but this was never required. Unit 1 announced cold shutdown at 1.24 am on 14 March and unit 2 followed at 3.52 am. Tepco has now announced that unit 4 achieved cold shutdown at 7.15 pm on 15 March. Water levels are now stable in all four reactors and offsite power is available, the company said.

2 As and a B · Post by **2 As and a B** » 16 Mar 2011, 10:26

Japanese news sources:

NHK WORLD TV live - Official NHK WORLD TV live on USTREAM. This is an English language 24-hour international news and information channel.

NHK World website - TV live and print news stories.

Also Kyodo News - print news stories and video clips.

UndercoverElephant · Post by **UndercoverElephant** » 16 Mar 2011, 11:00

foodimista wrote:
All Fukushima Daini units in cold shutdown

15 March 2011

All four units at the Fukushima Daini nuclear power plant have now achieved cold shutdown - where coolant water is at less than 100ºC - with full operation of cooling systems, Tepco reported. All the reactors shut down automatically during last week's earthquake and have remained safe. While unit 3's shutdown went as expected, damage to the emergency core cooling systems of units 1, 2 and 4 led to the announcement of emergency status. These three reactors were prepared for potential pressure release, but this was never required. Unit 1 announced cold shutdown at 1.24 am on 14 March and unit 2 followed at 3.52 am. Tepco has now announced that unit 4 achieved cold shutdown at 7.15 pm on 15 March. Water levels are now stable in all four reactors and offsite power is available, the company said.

Just in case anyone reading this does not realise, this is the other nuclear plant in Fukushima (Fukushima 2.)

2 As and a B · Post by **2 As and a B** » 16 Mar 2011, 13:50

Indeed.

Here are the nuclear sites and reactors in Japan.

Onagawa, the site nearest the earthquake epicentre has also shut down.

Fire at Tohoku Elec Onagawa nuclear plant -Kyodo

TOKYO, March 11 (Reuters) - A fire broke out at Tohoku Electric Power Co's (9506.T) Onagawa nuclear plant in northeastern Japan following Friday's major earthquake, Kyodo news agency said.

Prior to the Kyodo report, the company had said it had not received information on whether there had been any problems at the nuclear power plant after the disaster.

http://www.reuters.com/article/2011/03/ ... 1E20110311

Japan agency: Onagawa plant functioning properly

TOKYO, March 13 (Reuters) - Japan's nuclear safety agency said on Sunday there was no problem with the cooling process at Tohoku Electric Power Co's (9506.T) Onagawa nuclear power plant and that a rise in radiation levels there was due to radiation leakage at another plant in a neighbouring prefecture.

The agency said a report from Tohoku Electric shows that cooling systems at all three reactors at the Onagawa complex, which were automatically shut after a massive earthquake and tsunami on Friday, are functioning properly.

http://www.reuters.com/article/2011/03/ ... 8020110313

biffvernon · Post by **biffvernon** » 16 Mar 2011, 18:19

#4, on the left, now looks as much of a wreck as #3. #4 was the one that was not operational and I had not heard reports of a big explosion there, just a fire, but it looks pretty blasted.

So this is what happens when stored spent fuel is not looked after properly.

In future days, after the collapse of the global market economy and the end of reliable grid electricity, will we be able to care for spent fuel storage ponds?

Back to the now, it's good to see, after yesterday's media blackout, that we have pictures again. The damage to #4 is clearly far worse than was being suggested yesterday. Richard Black's report for the BBC will doubtless be criticised for being alarmist - unless the worst case scenario actually happens:

Transferred to the cooling pond, allowing technicians to do routine maintenance on the reactor, the rods are supposed to sit quietly until the time comes for their re-insertion or their journey towards disposal.

The tops of the rods are supposed to be about 5m (16ft) below the water surface.

The water keeps them cool and also blocks the release of gamma rays that would harm people in the vicinity.

So why is it that the Tokyo Electric Power Company (Tepco) has warned: "The possibility of re-criticality is not zero"?

If you are in any doubt as to what this means, it is that in the company's view, it is possible that enough fissile uranium is present in enough density to form a critical mass in the cooling pond - meaning that a nuclear fission reaction could start in the building, outside the containment shield that surrounds the actual reactor.

If it happened, this would lead to the enhanced and sustained release of radioactive materials - though not a nuclear explosion.

http://www.bbc.co.uk/news/science-environment-12762608